Turbopump structure



g- 12, 1952 L. l DREIBELBIS 2,606,501

TURBOPUMP STRUCTURE Filed July 21, 1948 v 2 SI-iEETS -SI-IEET 1INVENTOR. LOGAN L. DREIBELBIS BY ZDW ATTORNEYS A g- 1952 L. DREIBELBI'STURBOPUMP STRUCTURE Filed July 21, 1948 2 SHEETS-SHEET 2 INVENTOR. LOGANL DREIBELBIS Patented Aug. 12, 1952 UNITED STATES PATENT OFFICETURBOPUMP STRUCTURE Logan L. Dreibelbis, San Juan, Tex., assignor to TheM. Kellogg Company, Jersey City, N. .I., a corporation of DelawareApplication July 21, 1948, Serial No. 39,899

The present invention relates to a rotary power unit, and moreparticularly to means for cooling and lubricating the bearings thereof.

The provision of effective cooling and lubrication for the anti-frictionbearings in a rotary power unit, such as a high speed turbine is adifficult design problem. This is especially true when the motive fluiddriving the turbine rotor has a high initial temperature, as in the caseof a gas turbine, and where the unit is intended to be operated in anyposition, and at extremely high altitudes; as in an aircraft or otherairborne device, where only low density air is present and therefore notsuitable for use as a coolant or vehicle for a lubricant. In such apower unit, extreme care must be taken to insure adequate cooling andlubrication of the bearings to avoid any possibility of bearing failureand the resulting failure of thepower unit. Itis also essential that thecooling and lubricating means provided be compact and-light, in weighttopermit the power unit to meet the space and weight limitations thatnecessarily accompany airborne applications. p a

One object of the present invention is to provide new and improved meansfor; cooling .the

bearings of a rotarypower unit. 7

Another object of the present invention'is. to provide new andimprovedmeans'for lubricating the various bearings of a rotary power unit.

Another object of the present invention is to provide new and improvedmeans for cooling; and lubricating the various bearings of the rotarypower unit.

Another object of the present invention is to provide a positivelubricating arrangement for a turbine unit which is unaffected ,by theposition of the turbine unit in space. 7

Another object of the present invention is to provide a turbine unitcapable of operation at extremely high altitudes wherein means areprovided to cool and lubricate the bearings thereof.

Another object of thepresent invention is to provide a rotary powerunit, adapted to operate at high temperature I and. having ananti-friction bearing forming a part thereof,,with means for maintainingboth races of said anti-friction bearing at substantially the sametemperature.

Another object of the present invention is to provide a turbine andvpump unitadapted to pump a fuel, or oxidizing agent for a fuel to a.rocket motor and provided with means to;;utilizea portion of. said fuel,oroxidi'zin'g agent, forco oling the various bearings and/or lubricatingsystem o said turbine. p

4 Claims. (Cl. 103- 87) Other objects of the invention will in part beobvious and will in part appear hereinafter. V The invention accordinglycomprises the apparatus possessing the construction, combination ofelements and'arrangement of parts which are exemplified'in the followingdetailed disclosure, and the scope of itsapplication will be indicatedin the claims.

For a further understanding of the nature and objects of the inventionreference should be had to the following detailed description taken inconnection with the accompanying drawings where- Fig. l is a view mainlyin axial section and partly in side elevation of a gas turbine unitembodying the features of the present invention; and

Fig. 2 is an enlarged fragmentary view show ing details of the coolingand lubricating means for one of theanti-friction.bearings of Fig. 1.

The,present.invention is primarily concerned with providingmeans forcooling and lubricating the bearings of a gas turbineadapted to operateat high'altitudes to drive a pump to provide fluid .fuel,,an d/oroxidizingagent for said fuel, to a rocket motor. The present inventioncomprises a selfcontained; sealed lubricating system for predeterminedbearings in the turbine, whereby a mist of lubricant is circulatedthrough each bearing independent of thepresence or absence of outsideair, and which does not require a supply of gas underpressure, and meansfor cooling said bearings and said lubricating mist by means of a smallpercentage of the fluid pumped by the pump. After serving as a coolantthe fluid is returned to the pump for delivery to the rocket motor. Itwill be understood that the present invention can be applied to rotatingequipment of other types where it ;-is desirable or necessary to coolthe bearings-and insure highly eflicient lubrication.

Refcrringto the drawingthe rotary power unit of the present invention isshown in the form of a small high speed gas turbine comprising a hollowshaft l9 havingintegrally formed thereon a two-stage turbine wheel l2.:Shaft Ill and turbine stantially concentric; therewith.

Turbine wheel. I2 is shown as having two annular axially space'dseriesof blades 20 and 22 at its outer periphery which are separated by'anannular series of flxedblades 24 rigid. with the 63 mg M: The blades 2 0and 22 are preferably of the impulse type and constitute twomultivelocity stages, while the blades 24 serve as intermediate guideblades in a manner well known in the art.

Casing I4 is provided with a plurality of inlets 26 (only one is shownto avoid confusing the drawing) for the motive fluid, which may beexhaust gases or other highly heated gases coming from an associatedengine, or from a combustion chamber. Inlets 26 are spacedcircumferentially around casing I 4 and are in communication with theinterior of casing I4 in such a manner that the gas is directed into thefield of action of the first stage of blade 26. The exhaust side of thesecond stage of blades 22 communicates with an exhaust chamber 28 whichmerges into a conduit 30 by which the turbine exhaust may be carriedaway from the unit.

The casing I4 is shown as constituting two main sections 32 and 34.Casing section 32 includes the inlets 26 and casing section 34 includesthe exhaust chamber 28. Inlet casing section 32 carries a bearinghousing 36. Exhaust casing section 34 carries bearing housing 38.Bearing housings 36 and 38 respectively carry anti-friction bearings I6and I8 which serve to rotatively position turbine wheel I2 in the casingI4. An annular seal 40 is carried by bearing housing 36 betweenanti-friction bearing I6 and turbine wheel I2, and a similar annularseal 42 is carried by bearing housing 38 between antifriction bearing I8and turbine wheel I2. Annular eals 46 and 42 form a substantially gastight sliding seal between the interior of casing I4 and the interior ofbearing housings 36 and 38 and prevent the escape of motive gas fromcasing I4 into the interior of housings 36 and 38.

A centrifugal pump adapted to be driven by the turbine unit is carriedby bearing housing 36. The centrifugal pump comprises a pump housing 44,formed by a sleeve portion 46 and an end plate 48, and a centrifugalimpeller 50, comprising flange '52, vanes 54, and shroud plate 56,rotatively carried by shaft ID in said pump housing 44. The primaryfunction of the centrifugal pump formed by the housing 44 and impeller50 is to supply a rocket motor with liquid fuel, or an oxidizing agentfor fuel, by drawing the liquid through axial pump inlet 58 in an endplate 48, and passing the liquid on to the rocket motor by means ofannular chamber 60, which receives said liquid under pressure fromimpeller 50, and discharge duct 62, which communicates with annularchamber 60, and which conducts the fluid to the rocket motor, or to aconduit for that purpose. The present invention utilizes a portion ofthe output of the centrifugal pump to cool bearingsI6 and I8 of theturbine unit, and to cool the lubricant used to lubricate said bearings.After serving as a coolant for bearings I6 and I8, and the lubricanttherefore, the fluid is returned to the lower pressure side of the pump.

A sealingring 64 is carried by housing sleeve 46 and located closelyadjacent to impeller 50. A slight clearance 66 is provided betweenflange 52 and sealing ring 64, and a sliding seal is provided betweenthe inner peripheral surface of Said Sealing ring 64 and the hub ofimpeller 56. When the above described centrifugal pump is in operationit is inevitable that a slight amount of the fluid under pressure willpass through clearance 66 and will make its way through the sliding sealbetween sealing ring 64 and the hub of impeller 50. It is customary incentrifugal pumps of this general type to take care of this leakage byproviding some means for collecting the fluid and removing it from thepump housing 44 to prevent its building up a dangerously high pressuretherein. However, the present invention takes advantage of the leakageor seepage of fluid around the impeller by using the fluid that thusleaks around impeller 50 as a coolant for the bearings of the gasturbine which drives the centrifugal pump.

An annular passage 68, formed by a portion of the inner peripheral wallof sleeve portion 46, sealing ring 64, the hub of impeller 50, shaft I0,and inner sealing ring 69, is provided to collect the fluid as it passesthrough the seal provided by sealing member 64 and the hub of impeller50. A radial passage III is provided through the hub of impeller 50 andshaft II) to permit communication between annular passage 68 and hole orbore II in shaft III. Hole or bore II is provided with concentric tubesI2 and 14 which function as heat barriers and to direct the flow offluid entering said bore II first in a direction towards the exhaust endof shaft II] to cool bearings I6 and I8, and then back along the centralportion thereof and into inlet opening 58. To accomplish this, tube I2,having one of its ends journaled in axial hole 11 in impeller attachingand fairing device 90, extend axially throughout the length of bore II,and has its other end journaled in bore plug I9, to form annular spaces86 and 86 adjacent bearings I6 and I8 respectively. Fluid collected inannular passage 68 passes from said passage 68 through radial passage IOinto and along annular space 88 cooling shaft Ill, and by conduction,cooling the inner races of anti-friction bearings I 6. It is desirable,to insure the efficient utilization of the high temperature turbinemotive fluid, that any great amount of heat loss from turbine wheel I2be prevented. It is also desirable to provide antifriction bearing I8with cooling fluid. Therefore, a heat barrier, comprising a secondconcentric tube I4, is located between tube I2 and the wall of bore I Iand spaced between anti-friction bearings I 6 and I8, to form annularspace 64between itself and tube 12, andinsulating space I6 locatedbetween itself and the wall of bore I I. The cooling fluid leavesannular space 88 and enters annular space 84 by passing through openings82 in concentric tube I4. Insulated from the intense heat of rotor I2 bymeans of tube I4 and insulating space I6, the cooling fluid passesthrough annular space 84 and enters annular space 86 adjacentanti-friction bearing I8. The cooling fluid there cools the shaft I0,and by conduction cools the inner race of anti-friction bearing I8. Thecooling fluid then leaves annular space 86 and enters concentric tube I2through openings 88 in the wall thereof, and returns to the inlet of thecentrifugal pump through said tube 12 and axial opening I! and radialholes I8 in impeller attaching and fairing device 90.

Means are also provided whereby a small amount of the liquid pumped bythe centrifugal pump is used to cool the outer races of, and thelubricant for, anti-friction bearings I6 and I8. Passageway 92 isprovided in end plate 48 and serves as a means for trapping and removinga predetermined amount of high pressure fluid from the annular chamber60. Tube 94 is connected to passageway 92 by means of fitting 96.Bearing housings 36 and. 38 are respectively provided with winding orlabyrinthlik'e passageways 98 and I00, which provide coolantpassages in,and extending completely around, the walls of their respective bearinghousings. Passageways 98 and I can be formed, if housings 36 and 38 arecast, by means of cores, or they can be machined by drilling diagonalholes, longitudinally of said housings 36 and 38, joined to each otherat their ends, and by plugging the holes where they extend through theends of said housings. Cooling fluid is supplied to passageways 98 andI00 by means of tube 94. After the cooling fluid has circulated aroundbearing housings 36 and 38 through passageways 98 and I00, the fluid isreturned to the centrifugal pump by means of a second tube (not shown)and admitted to the low pressure side of said pump through opening I02.It will thus be seen that the outer bearing races of antifrictionbearings I6 and I8 are cooled by circulating a coolant through bearinghousings 36 and 38 to cool said housings which in turn cool said outerbearing races by conduction, and by cooling the supply of lubricantwhich is circulated through bearings I6 and I8 in a manner to beexplained more in detail later.

The present invention also includes a lubricating system foranti-friction bearings I6 and I8. A bearing locating and supportingsleeve I08 is located in bearing housing 36. The outer races ofanti-friction bearing I6 are supported by sleeve I08 and are accuratelypositioned axially of housing 36 by means of flange I09 formed on theinner end of sleeve I66. An annular space I06 is provided in housing 36adjacent the inner end of bearing I6, and a centrifugal impeller orblower I04, rotatably carried by shaft I0, is located in said space I06.Bearing end plate H2 and sealing ring II4 enclose and seal anti-frictionbearings I6 in housing 36. Bearing end plate II2 by means of flange II3,forming a part thereof, holds the outer races of anti-friction bearingsI6 in sleeve I08 and against flange I09. The inner end of sealing ringII4 holds the inner races of bearings I6 in position on shaft I0 andagainst bearing shoulder I05 formed thereon. The inner ends, or sides,of bearing end plate H2 and sealing ring II4 cooperate to provide anannular space I I6 at the outer end of bearings I6. Communicationbetween the outer portions of annular spaces I06 and H6 is provided bymeans of a plurality of milled slots forming longitudinal channels orsplines H0 in the outer periphery of bearing sleeve I08, a plurality ofmilled slots I I5 forming radial passages in flange H3, and a pluralityof drilled holes II I in bearing sleeve I08 connecting channels orsplines IIO with milled slots H5. It will thus be seen that a pluralityof continuous passages are provided comprising the longitudinal channelsor splines I I0, the milled slots I I5, and the holes II I, whichconnect the outer portions of annular spaces I06 and H6, and the spacebetween the inner and outer races of anti-friction bearing I6 whichconnects the inner portions of annular spaces I06 and H6. Two openingsH8 and I20 are provided through bearing sleeve 36 to give access toannular space I06. Opening H8 permits a predetermined quantity oflubricant to be placed in annular space I06, and opening I20 permits thelubricant to be drawn out of said annular space I06.

To lubricate anti-friction bearing I6 by means of the above describedlubricating system a predetermined quantity of lubricant, which may beone of the silicone lubricants or any other suitable lubricant, isadmitted to annular space I06 through opening I18 and opening H8 isclosed by means of plug I22, and the gas turbine is started. Shaft I0rotatescentrifugal impeller or blower I04 causing said impeller I04tothrow the lubricant, contained in annular space I06, outwardly in saidspace I06. The lubricant then passes longitudinally through channels H0and holes III, and radially inwardly through radial passages II5 toenter annular space II6. From annular space II6 the lubricant passesthrough the space between the inner and outer, races of anti-frictionbearing I6 to cool and lubricate said bearing and to return to annularspace I06. As the speed of the turbine increases the speed at which thelubricant circulates also increases until the lubricant and the aircontained in housing 36 are completely and thoroughly mixed to form alubricating mist or fog which is rapidly circulated through the abovedescribed continuous passageways. The mist or fog of lubricant, inaddition to lubricating the bearing l6, also serves to further cool thebearing inasmuch as said mist of lubricant in passing throughlongitudinal channels I I0 and holes III comes in contact with thebearing housing 36 and bearing sleeve I08 which, as above described, arecooled by the'fluid circulated through passageway 98, and is thus cooledbefore passing through bearing I6.

Anti-friction bearing 18 is provided with a lubricating systemsubstantially identical to the lubricating system above described. inconnection with anti-friction bearing I6. The lubricating system foranti-friction bearing I8 comprises a centrifugal impeller I24, anannular space I26, bearing sleeve I28, longitudinal channels I30, holesI3I, and bearing end plate I32 and bearing seal I34, which together formannular space I36. All of these elements cooperate to provideanti-friction bearing I8 with a lubricating system similar in structureand function to the lubricating. system for anti-friction bearing I6.

Two means for-cooling both bearings I6 and I8 are provided. The fluidflowing through hollow shaft I0 cools the inner races of both bearings,and the fluid flowing through the two bearing housings 36 and 38 coolsthe outer races of both bearings, and the lubricant for the bearings.The combination of means'to cool both the outer and inner races of thebearings is highly desirable to eliminate any possibility of bearingfailure due to overloading or excess bearing play brought about byunequal expansion of the inner and outer races. For example, if only theouter bearing races were cooled, the inner races, due to the fact thatthey would be elevated to a higher temperature than the outer races,would expand a greater amount proportionally than said outer races. Thiswould decrease the space between the inner and outer races, resulting ina much higher loading on the balls, or rollers, than they are designedto withstand and thus cause bearing fail ure in a short period of time.If only the inner races were cooled the outer races would expand agreater amount proportionally than said inner races. This would increasethe space between the inner and outer races, resulting in excessivebearing clearance and play. At best excessive bearing clearance and playin high speed rotating equipment will reduce its efficiency, and canresult in bearing failure.

The present invention makes it possible to cool both the inner and outerbearing races, and by controlling the flow of cooling fluid throughhollow shaft I 0 and through bearing housings 36 and 38 the two racescan be maintained at substantially the same'temperature, thusmaintaining the proper bearing clearance and loading at all times.

Since certain changes may be made in the above apparatus withoutdeparting from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawing shall be interpreted as illustrative and not ina limiting sense.

What is claimed is:

1. In a turbopump unit, a turbine wheel and a pump, a hollow shaft forsaid turbine wheel, a bearin for said shaft, a p mp impeller mounted onsaid shaft, means comprising an annular passage surroundin said shaftadapted to collect fluid leaking from said pump, an opening through thewall of said shaft communicating between said annular passage and saidshaft, means in said shaft adapted to cause liquid entering saidshaftthrough said opening in the wall thereof to flow through said shaftadjacent said wall to cool said shaft and said bearing, and to flow alonthe center of said shaft in an opposite direction for return to saidpump, and means for conducting said liquid to said pump.

2. In a turbopump unit, a turbine wheel and a pump, a shaft for saidturbine wheel, said shaft having a longitudinal bore therein, a bearinfor said shaft, a centrifugal pump impeller mounted on said shaft, meanscomprising an annular passage surrounding said shaft adapted to collectfluid leaking from the high pressure side of said pump, an openingthrough the wall of said shaft providing communication between saidannular passage and said longitudinal bore, means in said longitudinalbore adapted to cause liquid entering said shaft through said opening inthe wall thereof to flow along said longitudinal bore adjacent said wallto cool said shaft and said bearing, and to flow along the center of'saidlongitudinal bore in an opposite direction for return to the lowpressure side of said pump, and means for leading said liquid to saidpump.

3. In a rotary power unit comprising a rotor,

a hollow shaft for said rotor, an anti-friction bearing supportingsaid-shaft, said bearing having an outer race and an inner race, ahousing for said bearing, and a pump adapted to be driven by said shaft,the combination of a coolant passage in said housing, means fordiverting a predetermined part of the output of said pump to saidcoolant passage to cool said outer race, and means for diverting anotherpart of the output of said pump to said hollow shaft to cool said innerrace, said two part of said pump output being such that said two bearingraces are maintained at substantially the same temperature.

4. In a rotary power unit, a rotor, a hollow shaft for said rotor, ananti-friction bearing, having an inner race and an outer race, supportinsaid shaft, a housing for said bearing, said housing having a coolantpassage and an annular space at each end of said bearing, meansproviding communication between said annular spaces, means located inone of said annular spaces for circulating a lubricant through saidcommunication means and said bearing, a pump adapted to be driven bysaid shaft, means for diverting a predetermined part of the output ofsaid pump to said coolant passage to cool said outer bearing race andaid lubricant, and means for diverting another part of the output ofsaid pump to said hollow shaft to cool said inner bearing race, said twoparts of said pump output bein such that said two bearing races aremaintained at substantially the same temperature.

LOGAN L. DREIBELBIS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Kendall June 27, 1944

